DESCRIPTION: The investigators propose to test the feasibility of developing sigma-2 receptor-binding radiopharmaceuticals for potential use in imaging breast tumors, as further described by their abstract: "The goal of this STTR application is to develop 99mTc-labeled sigma-2 (omicron2) receptor imaging agents for Single Photon Emission Computed Tomography (SPECT) studies of breast cancer. This approach is based on the observation that omicron2 receptors are expressed in high density in a number of human tumors, including breast tumors. Our preliminary data also indicate that 99mTc-labeled omicron2 receptor imaging agents radiotracers can not only be used in the anatomical imaging of breast tumors, but may also provide information regarding the proliferative status of breast cancer. An additional incentive for focusing on omicron2 receptors stems from our development of two new omicron2-selective compounds, having either a tropane or granatane ring system, that will serve as lead compounds for SPECT radiotracer development. There are currently no omicron-selective radiotracers for SPECT imaging studies of breast cancer. The strategy chosen for incorporating 99mTc into the tropane and granatane ring systems will use established methods developed for making 99mTc-labeled receptor imaging agents. Although the proposed radiopharmaceuticals will initially benefit the diagnosis and treatment of breast cancer, we believe the technology developed in this STTR application will translate to other human cancers (prostate tumors, lung carcinoma, gliomas) that possess a high density of omicron2 receptors." PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE